Comparison of a multi-res <> single-res medium sized pano
Posted: Mon Oct 25, 2010 7:33 pm
Hello Forum,
To get the differences between multi-res and single-res medium sized panoramas a bit more clear I made a comparison of both versions.
The scene is the WWII cemetery/memorial at Margraten, the Netherlands.
This is the multi-res version (200KB, tiles 14,4MB) :
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_001.html
The same multi-res pano but now with some colored tiles in it to make the switch between the levels visible and to check the image quality of the transition, when zooming in/out and when resizing the browser window you can clearly see the switch of the 4 levels (the tiles of the smallest resolution are not colored).:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_002.html
This is the single-res version (7.7MB):
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_003.html
This is a Zoomify image of the equirectangular (10336 × 5168 px), when you open the equirectangular in a separate browser window and zoom in to 100% then it is easy to compare the image quality to the panoramas:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_004.html
This is a screenshot of the multi-res panorama settings:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_005.html
The smallest resolution only serves as a workaround for the lack of a preview image, because my panos are aimed at standard monitors I didn't bother to change the Switch Bias and/or apply extra low resolution levels for use on mobile devices.
In some previous experiments I found out that with the default size jump of the levels the switch of the levels is to much visible when zooming in (unsharp<switch>sharp) and that is why I reduced the size jump.
Each tile level is now approx. 70% of the tile size of the above level (instead of 50% with the default setting), the downsize of this is a larger total file size and so a larger total download time but imo the gain in image quality makes it worth.
On my monitor with 1920x1200 px the multi-res pano shows level 4 (pink tiles) after loading, when reducing the monitor resolution to 1024x768 px then level 2 (sepia tiles) is showed.
Advantages of multi-res compared to single-res for medium sized panos:
-Much less shimmering of straight lines when zooming in/out, especially on smaller monitors shimmering can be very annoying, to see what I mean reduce the window of the normal pano and zoom in/out a bit,
-The loading time to show an initial view of the pano is shorter (depending on the multi-res settings, the download speed and the monitor resolution).
Disadvantages:
-The large number of tiles and the larger total file size can makes the total loading time a lot longer with a slow internet connection,
-For a fast upload to the web space the files needs to be zipped and after the upload the files needs to be remote unzipped (uploading unzipped files can takes a very long time).
-there is (little) more work involved.
To be honest I am not convinced if using multi-res is the best road to go for medium sized panos, for panos much larger then 10K this is the best option but for panos around 10K ?
This comparison is far from complete so I like to hear about your experiences, remarks, etc.
Wim
To get the differences between multi-res and single-res medium sized panoramas a bit more clear I made a comparison of both versions.
The scene is the WWII cemetery/memorial at Margraten, the Netherlands.
This is the multi-res version (200KB, tiles 14,4MB) :
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_001.html
The same multi-res pano but now with some colored tiles in it to make the switch between the levels visible and to check the image quality of the transition, when zooming in/out and when resizing the browser window you can clearly see the switch of the 4 levels (the tiles of the smallest resolution are not colored).:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_002.html
This is the single-res version (7.7MB):
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_003.html
This is a Zoomify image of the equirectangular (10336 × 5168 px), when you open the equirectangular in a separate browser window and zoom in to 100% then it is easy to compare the image quality to the panoramas:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_004.html
This is a screenshot of the multi-res panorama settings:
http://www.dmmdh.nl/panos/PANO2VR/pano2 ... e_005.html
The smallest resolution only serves as a workaround for the lack of a preview image, because my panos are aimed at standard monitors I didn't bother to change the Switch Bias and/or apply extra low resolution levels for use on mobile devices.
In some previous experiments I found out that with the default size jump of the levels the switch of the levels is to much visible when zooming in (unsharp<switch>sharp) and that is why I reduced the size jump.
Each tile level is now approx. 70% of the tile size of the above level (instead of 50% with the default setting), the downsize of this is a larger total file size and so a larger total download time but imo the gain in image quality makes it worth.
On my monitor with 1920x1200 px the multi-res pano shows level 4 (pink tiles) after loading, when reducing the monitor resolution to 1024x768 px then level 2 (sepia tiles) is showed.
Advantages of multi-res compared to single-res for medium sized panos:
-Much less shimmering of straight lines when zooming in/out, especially on smaller monitors shimmering can be very annoying, to see what I mean reduce the window of the normal pano and zoom in/out a bit,
-The loading time to show an initial view of the pano is shorter (depending on the multi-res settings, the download speed and the monitor resolution).
Disadvantages:
-The large number of tiles and the larger total file size can makes the total loading time a lot longer with a slow internet connection,
-For a fast upload to the web space the files needs to be zipped and after the upload the files needs to be remote unzipped (uploading unzipped files can takes a very long time).
-there is (little) more work involved.
To be honest I am not convinced if using multi-res is the best road to go for medium sized panos, for panos much larger then 10K this is the best option but for panos around 10K ?
This comparison is far from complete so I like to hear about your experiences, remarks, etc.
Wim